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Código PHP:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title></title>
<script>
function set_opacity(div, val) {
if (typeof div.filters!='undefined') {
val *= 100;
try {
div.filters.item("DXImageTransform.Microsoft.Alpha").opacity = val;
} catch (e) {
div.style.filter = 'progid:DXImageTransform.Microsoft.Alpha(opacity='+val+')';
}
} else {
div.style.opacity = val;
div.style.MozOpacity = val;
}
}
var transicion=function(inicio,fin,segundos){
var val=inicio+.0001;
set_opacity(this, val);
this.pasos=(fin-inicio)/100;
this.pausa=segundos*10;
var _this=this;
this.intervalo=setInterval(
function(){
if(val>=fin){
clearInterval(_this.intervalo);
_this.intervalo=null;
}
val=val+_this.pasos;
set_opacity(_this, val);
},this.pausa);
}
window.onload=function(){
var obj=document.getElementById('pp');
transicion.call(obj,0,1,5);
}
</script>
</head>
<body>
<div id="pp" style="background-color:#FF0000; width:100px;">EJEMPLO</div>
</body>
</html>